A Study of ERAS-007 as Monotherapy or in Combination With ERAS-601 in Patients With Advanced or Metastatic Solid Tumors

* To evaluate the safety and tolerability of ERAS-007 monotherapy administered once weekly (QW) and twice daily-once weekly (BID-QW). * To determine the Maximum Tolerated Dose (MTD) and/or Recommended Dose (RD) of ERAS-007 monotherapy administered BID-QW. * To characterize the pharmacokinetic (PK) profile of ERAS-007 monotherapy. * To determine the optimal dose and schedule of ERAS-007 monotherapy. * To evaluate antitumor activity of ERAS-007 in various solid tumors. * To evaluate the safety and tolerability of ERAS-007 (BID-QW) and ERAS-601 (twice daily for three weeks on and 1 week off (BID 3/1)) when administered in combination. * To determine the Maximum Tolerated Dose (MTD) and/or Recommended Dose (RD) of ERAS-007 administered in combination with ERAS-601. * To characterize the pharmacokinetic (PK) profile of ERAS-007 and ERAS-601 when administered in combination. * To evaluate antitumor activity of ERAS-007 and ERAS-601 when administered in combination in various solid tumors * To evaluate antitumor activity of ERAS-007 and ERAS-601 when administered in combination in various solid tumors

Inclusion Criteria: * Age ≥ 18 years. * Willing and able to give written informed consent. * Have histologically or cytologically confirmed advanced or metastatic solid tumor with a relevant molecular alteration (as applicable). * There is no available standard systemic therapy available for the patient's tumor histology and/or molecular biomarker profile; or standard therapy is intolerable, not effective, or not accessible; or patient has refused standard therapy. * Recovered from all toxicities associated with prior treatment to acceptable baseline status. * Have ECOG performance status of 0 or 1 with an anticipated life expectancy of \> 12 weeks. * Willing to comply with all protocol-required visits, assessments, and procedures. * Able to swallow oral medication. Exclusion Criteria: * Currently receiving another study therapy or has participated in a study of an investigational agent and received study therapy within 4 weeks of the first dose of ERAS-007. * Received previous treatment with an ERK inhibitor. * For participants being considered for ERAS-007 + ERAS-601 (Part D): prior treatment with SHP2 inhibitor. * For participants being considered for ERAS-007 + ERAS-601 (Part D): documented PTPN11 mutations * Received prior antineoplastic therapy within \< 21 days or 5 half-lives, whichever is shorter. * Received prior palliative radiation within 7 days of first dose of ERAS 007 or ERAS-601, * Received previous treatment with a MAPK inhibitor that resulted in discontinuation due to unacceptable toxicity. * Prior surgery (e.g., gastric bypass surgery, gastrectomy) or gastrointestinal dysfunction (e.g., Crohn's disease, ulcerative colitis, short gut syndrome) that may affect drug absorption. * Have any underlying medical condition, psychiatric condition, or social situation that, in the opinion of the Investigator, would compromise study administration as per protocol or compromise the assessment of AEs. * Are pregnant or breastfeeding or expecting to conceive or father children within the projected duration of the trial.